US3775841A - Method of adjusting the dimensions of sintered ferromagnetic cores - Google Patents

Method of adjusting the dimensions of sintered ferromagnetic cores Download PDF

Info

Publication number
US3775841A
US3775841A US00184696A US3775841DA US3775841A US 3775841 A US3775841 A US 3775841A US 00184696 A US00184696 A US 00184696A US 3775841D A US3775841D A US 3775841DA US 3775841 A US3775841 A US 3775841A
Authority
US
United States
Prior art keywords
dimensions
core
coil
sintered
adjusting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00184696A
Inventor
F Lathouwers
Groot J De
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Philips Corp
Original Assignee
US Philips Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3775841A publication Critical patent/US3775841A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0206—Manufacturing of magnetic cores by mechanical means
    • H01F41/0246—Manufacturing of magnetic circuits by moulding or by pressing powder
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H01F27/255—Magnetic cores made from particles
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F37/00—Fixed inductances not covered by group H01F17/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0206—Manufacturing of magnetic cores by mechanical means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/236—Manufacture of magnetic deflecting devices for cathode-ray tubes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F17/00—Fixed inductances of the signal type 
    • H01F17/04—Fixed inductances of the signal type  with magnetic core
    • H01F2017/048—Fixed inductances of the signal type  with magnetic core with encapsulating core, e.g. made of resin and magnetic powder
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/04—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing coils
    • H01F41/06—Coil winding
    • H01F41/071—Winding coils of special form
    • H01F2041/0711—Winding saddle or deflection coils
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/4902—Electromagnet, transformer or inductor
    • Y10T29/49071—Electromagnet, transformer or inductor by winding or coiling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/4902—Electromagnet, transformer or inductor
    • Y10T29/49075—Electromagnet, transformer or inductor including permanent magnet or core
    • Y10T29/49076—From comminuted material

Definitions

  • ABSTRACT r A method of adjusting the dimensions of sintered ferromagnetic coil cores by coating the cores in a mold with a layerrof coating material consisting of a binder Y and a ferromagnetic powder.
  • gthiS. object is achieved in that after sintering, before'the core is provided with a; winding to form a coil or transformer, at least a portion of the surface of the core is coated ina mold with a layer of coating material consisting of a mixture of a binder and a ferromagnetic powder The coating material can be pressed or injected into the mold in a known. manner. The ultimate surface of the.
  • coated portion of the core isan accurate impression of the corresponding surface of thernould.
  • The. coating material generally-has a lower magnetic permeability-than the sintered material of the .core. This means that in coils having an air gap" whose width isto be accurately defined, also'the thickness and the permeability of the coating materialhave t'o be'taken int'oaccount'for' calculatingthe-widthof the "air gap.
  • FIG. 1 is an axial sectional view of a cylindrical coil whose core is manufactured by the method according to the invention
  • FIG. 2 is a partly axial sectional view of a deflection coil assembly, the yoke ringofwhich has not been treated aftersintering, and
  • FIG. 3 is a partly axial sectional view .ofa deflection coil assembly whose yoke ringhas been given the correct' dimensions after sintering by themethod according to the invention.
  • the coil shown in FIG. 1 comprises a cylindrical winding 1 which is wound on a central cylinder 3 hav-' ing connecting wires 4.
  • This central cylinder will generally be ferromagnetic. If the central cylinder 3 is sintered from ferromagnetic material,-the dimensions of its outer surfacecan be controlled-without much difficulty, for example, by'centerless grinding. As a result, the outer diameter of the winding 1 has a small tolerance..
  • a hollow,.outer cylinder 5 made of sintered ferromagnetic material, said cylinder constituting the core of the coil in co'njunction with the central cylinder 3.
  • an air gap 6 Between the hollow outer cylinder 5 and the winding 1 is situated an air gap 6, the width tolerance of which is determined mainly by the variations possible in the inner diameter of the'outer cylinder 5.
  • the inner side of the outer cyIinderS is raised in a mold. by providing a layer of coating material 7,
  • a binder for example,polythene
  • a a thickness'd corresponds toi'an airgap having a width d/pJ.
  • a favorable compromise can .be ob-' tained by means of a coating material whose permeabilferromagnetic powder,'for example, ferrite;
  • the layer 7 partly fills the air gap 6.
  • Variations in the dimensions of the outer cylinder 5 merely cause thickness variations inthe layer 7, without affecting the width of the air-filledportion 8 of. the air gap 6.
  • the total effective width of the air gap 6 is equal to the width of the airfilled portion 8 plus the thickness of the layer 7, divided by the permeability of the coatingfmateriaLsaid permeability preferably amounting to 10;.
  • This rneansthat a variation of 0.1 .mm inthe-thickness of layer ,7, caused by the tolerance of the l1ollow. outer cylinder 5, corresponds to a'variation. of"only 0.0l .mm. inthe total'effective width of the air gap 6.
  • each of the connecting wires 4 can be secured-in'the (hollow) central cylinder by means of a plug 9 of the same material as the layer 7.
  • Th e plug 9 can be conity has a value of approximately 10 after hardening of the'binder. Thickness variations in the coating material tion of the plug 9 extending outsidethe central cylinthen correspond to 'width variations of the air gap whichfare 10 times as small, which is in view of the usual tolerances of sintered cores fullyacceptable for most applications.
  • r i It is to be noted that the surrounding of a coil bya moulding compound is known, for example, from Swiss Pat. Spec; No. 228,763. The windings of the coil, however, are then embedded in 'the moulding compound, after'they have been provided on the core, so as to increase the inductance, thus forming an integral unit.
  • Providing the winding 1 on the central cylinder 3 can be facilitated by imparting a conical surface to the porj der, so that a gradual change-over from the diameter of of saddle coils 11 for the frame deflection (the pair of line deflection coils provided within the frame coils is omitted for the sake of clarity).
  • the coil pair 11 is surrounded by a yoke ring-13 of sintered ferrite, having a flared inner surface which has not been treated after sintering.
  • the Figure clearly illustrates that a yoke ring 13 which has shrunk only slightly more than the ring 13, will take in a position which has shifted considerably in the axial direction.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Coils Or Transformers For Communication (AREA)
  • Soft Magnetic Materials (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
  • Powder Metallurgy (AREA)

Abstract

A method of adjusting the dimensions of sintered ferromagnetic coil cores by coating the cores in a mold with a layer of coating material consisting of a binder and a ferromagnetic powder.

Description

1111 3,775,341 Dec. 4, 1973 METHOD OF ADJUSTING TIIE DIMENSIONS OF SINTERED FERROMAGNETIC CORES [75] Inventors: Franciscus Johannes Maria Lathouwers; Jacob De Groot, both Emmasingel, Eindhoven,
Netherlands [73] Assignee: U.S. Philips Corporation, New
York, N.Y.
[22] Filed: Sept. 29, 1971 211 App]. No.2 184,696
[30] Foreign Application Priority Data Oct. 9, 1970 Netherlands iw 7014813 52 u.s.c1 11 /605, 29/605, 29/608,
[51] Int. Cl. .i H0lf 41/02 [58] Field of Search 336/83, 233, 212;
[56] References Cited UNITED STATES PATENTS 3,325,760 6/1967 Bernard 336/83 X 476,816 6/1892 Pfannkuche 336/83 683,954 l0/l90l Liebreich........ 336/233 X 2,118,291 5/1938 Bollman 336/233 FOREIGN PATENTS OR APPLICATIONS 214,780 1924 Great Britain 336/83 Primary ExaminerThomas J. Kozma Attorney-Frank R. 'Trifari [57] ABSTRACT r A method of adjusting the dimensions of sintered ferromagnetic coil cores by coating the cores in a mold with a layerrof coating material consisting of a binder Y and a ferromagnetic powder.
2 Claims, 3 Drawing Figures FigJ - INVENTORJ FRANClSCUS' J.M.LATHOUWERS JACOB DE GROOT BY Z M Q METHOD OF ADJUSTING TIIE DIMENSIONS OF The invention will now be described with reference SINTERED FERROMAGNETIC CORES The invention relates to a method of accurately ad justing the dimensions of sintered ferromagneticcores for coils of transformersl I A treatment of this kind'is required ments are imposed as regards the shape' and the dimensions of the surface of the core, because the core is con siderably deformed'during sintejring. Such. severe requirern'ents are imposed; for example, for coils whose core has to have an accurat ely definedair gap and for cores for deflection coil a'ssemblies,the so-termed yoke rings, which have to fit accurately around the deflection coils.
According to a known method (see, for example,
Netherlands Pat. application No. 6909344), the mate-- I cated surface can be'controlled quickly and inexpen-.
sively. According to the invention gthiS. object is achieved in that after sintering, before'the core is provided with a; winding to form a coil or transformer, at least a portion of the surface of the core is coated ina mold with a layer of coating material consisting of a mixture of a binder and a ferromagnetic powder The coating material can be pressed or injected into the mold in a known. manner. The ultimate surface of the.
coated portion of the core isan accurate impression of the corresponding surface of thernould. I I
The. coating material generally-has a lower magnetic permeability-than the sintered material of the .core. This means that in coils having an air gap" whose width isto be accurately defined, also'the thickness and the permeability of the coating materialhave t'o be'taken int'oaccount'for' calculatingthe-widthof the "air gap. A
' layer of coatirig' material having a permeability .4. and
if severe requireprovide a method to the accompanying drawing, in which:
FIG. 1 is an axial sectional view of a cylindrical coil whose core is manufactured by the method according to the invention,
FIG. 2 is a partly axial sectional view of a deflection coil assembly, the yoke ringofwhich has not been treated aftersintering, and
FIG. 3 is a partly axial sectional view .ofa deflection coil assembly whose yoke ringhas been given the correct' dimensions after sintering by themethod according to the invention. a
The coil shown in FIG. 1 comprises a cylindrical winding 1 which is wound on a central cylinder 3 hav-' ing connecting wires 4. This central cylinder will generally be ferromagnetic. If the central cylinder 3 is sintered from ferromagnetic material,-the dimensions of its outer surfacecan be controlled-without much difficulty, for example, by'centerless grinding. As a result, the outer diameter of the winding 1 has a small tolerance..
Provided coaxially with thecentral cylinder 3 is a hollow,.outer cylinder 5 made of sintered ferromagnetic material, said cylinder constituting the core of the coil in co'njunction with the central cylinder 3. Between the hollow outer cylinder 5 and the winding 1 is situated an air gap 6, the width tolerance of which is determined mainly by the variations possible in the inner diameter of the'outer cylinder 5. In order to reduce this tolerance, the inner side of the outer cyIinderS is raised in a mold. by providinga layer of coating material 7,
consisting of a binder, for example,polythene, and a a thickness'd corresponds toi'an airgap having a width d/pJ. This demonstrates thatg'since the coating-layer is to compensate for the sintering'tolerances and hence has a thickness which varies for each individual product, it is desirable for proper reproducibility that the permeability of thecoating material is as large as possible. On the other hand,the quantity of binder may not be too small so as not to reduce the moldability of the coating material. A favorable compromise can .be ob-' tained by means of a coating material whose permeabilferromagnetic powder,'for example, ferrite; The layer 7 partly fills the air gap 6.- Variations in the dimensions of the outer cylinder 5 merely cause thickness variations inthe layer 7, without affecting the width of the air-filledportion 8 of. the air gap 6. The total effective width of the air gap 6 is equal to the width of the airfilled portion 8 plus the thickness of the layer 7, divided by the permeability of the coatingfmateriaLsaid permeability preferably amounting to 10;. This rneansthat a variation of 0.1 .mm inthe-thickness of layer ,7, caused by the tolerance of the =l1ollow. outer cylinder 5, corresponds to a'variation. of"only 0.0l .mm. inthe total'effective width of the air gap 6. 1
tween the central cylinder 3 and the outer cylinder '5 each of the connecting wires 4 can be secured-in'the (hollow) central cylinder by means of a plug 9 of the same material as the layer 7. Th e plug 9 can be conity has a value of approximately 10 after hardening of the'binder. Thickness variations in the coating material tion of the plug 9 extending outsidethe central cylinthen correspond to 'width variations of the air gap whichfare 10 times as small, which is in view of the usual tolerances of sintered cores fullyacceptable for most applications. r i It is to be noted that the surrounding of a coil bya moulding compound is known, for example, from Swiss Pat. Spec; No. 228,763. The windings of the coil, however, are then embedded in 'the moulding compound, after'they have been provided on the core, so as to increase the inductance, thus forming an integral unit. A
v method of this kind,-consequently-, cannot be used, for
example, for giving a yoke ring the correct shape or for providing a coil core with an accurately defined air gap.
nected to the'outer cylinder 5 by means of a disc 10 which is also formed from the same material.
Providing the winding 1 on the central cylinder 3 can be facilitated by imparting a conical surface to the porj der, so that a gradual change-over from the diameter of of saddle coils 11 for the frame deflection (the pair of line deflection coils provided within the frame coils is omitted for the sake of clarity). The coil pair 11 is surrounded by a yoke ring-13 of sintered ferrite, having a flared inner surface which has not been treated after sintering. The Figure clearly illustrates that a yoke ring 13 which has shrunk only slightly more than the ring 13, will take in a position which has shifted considerably in the axial direction. I
This drawback does not occur with the yoke ring shown in FIG. 3 and surrounding a similar coil assembly as in FIG. 2. The flared inner side of the yoke ring 15 is raised in a mould by coating with a layer of coating material 17 of the same composition as the layer 7 in FIG. 1. Consequently, the inner surface of the yoke ring 15 always adjoins the comparatively accurately reproducible outer surface of the coil pair 11 in the same manner, so that the yoke ring 15 will always take in the same position with respect to this coil pair in the axial direction.
mately 10.

Claims (1)

1,. A method of accurately adjusting the dimensions of a sintered ferromagnetic core for a coil or transformer, comprising the steps of, placing the core in a mold, applying to at least a portion of the surface of the core a layer of coating material consisting of a mixture of a binder and a ferromagnetic powder while in said mold, and thereafter winding a coil on said core. 2,. A method as claimed in claim 1, wherein the magnetic permeability of the coating material is approximately 10.
US00184696A 1970-10-09 1971-09-29 Method of adjusting the dimensions of sintered ferromagnetic cores Expired - Lifetime US3775841A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
NL7014813A NL7014813A (en) 1970-10-09 1970-10-09
US18469671A 1971-09-29 1971-09-29
US00388256A US3829806A (en) 1970-10-09 1973-08-14 Sintered ferromagnetic core having accurately adjusted dimensions

Publications (1)

Publication Number Publication Date
US3775841A true US3775841A (en) 1973-12-04

Family

ID=27351608

Family Applications (2)

Application Number Title Priority Date Filing Date
US00184696A Expired - Lifetime US3775841A (en) 1970-10-09 1971-09-29 Method of adjusting the dimensions of sintered ferromagnetic cores
US00388256A Expired - Lifetime US3829806A (en) 1970-10-09 1973-08-14 Sintered ferromagnetic core having accurately adjusted dimensions

Family Applications After (1)

Application Number Title Priority Date Filing Date
US00388256A Expired - Lifetime US3829806A (en) 1970-10-09 1973-08-14 Sintered ferromagnetic core having accurately adjusted dimensions

Country Status (5)

Country Link
US (2) US3775841A (en)
DE (1) DE2146113A1 (en)
FR (1) FR2110320B1 (en)
GB (1) GB1322092A (en)
NL (1) NL7014813A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4264683A (en) * 1978-07-26 1981-04-28 Permacoraltair, Inc. Metallic inductor cores
US4647890A (en) * 1986-05-15 1987-03-03 Battelle Development Corporation Molded ferromagnetic return circuit for a solenoid

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5230113A (en) * 1975-09-02 1977-03-07 Sony Corp Deflecting device of in-line type color cathode-ray tube
DE2805562C2 (en) * 1978-02-10 1984-08-02 Kuka Schweissanlagen + Roboter Gmbh, 8900 Augsburg Device for welding a workpiece with a tubular cross-section at the welding point to a second workpiece
NL8004200A (en) * 1980-07-22 1982-02-16 Philips Nv PLASTIC-BONDED ELECTROMAGNETIC COMPONENT AND METHOD FOR MANUFACTURING THE SAME
US5166655A (en) * 1988-02-16 1992-11-24 Gowanda Electronics Corporation Shielded inductor
US5015982A (en) * 1989-08-10 1991-05-14 General Motors Corporation Ignition coil
CN113776337B (en) * 2021-10-15 2024-01-16 海宁市海铖电子有限公司 Prevent microstructure manganese zinc ferrite magnetic core soaking sintering device of fracture

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US476816A (en) * 1892-06-14 And alfred pfxnn
US683954A (en) * 1900-11-30 1901-10-08 Frederick Rohnert Telephone-transformer.
GB214780A (en) * 1923-11-13 1924-05-01 Sydney Harold Varnals Improvements in stationary electrical transformers
US2118291A (en) * 1936-05-06 1938-05-24 Commw Mfg Company Arc welding unit
US3325760A (en) * 1965-10-01 1967-06-13 Gen Motors Corp Electromagnet with resinous ferromagnetic cladding

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US476816A (en) * 1892-06-14 And alfred pfxnn
US683954A (en) * 1900-11-30 1901-10-08 Frederick Rohnert Telephone-transformer.
GB214780A (en) * 1923-11-13 1924-05-01 Sydney Harold Varnals Improvements in stationary electrical transformers
US2118291A (en) * 1936-05-06 1938-05-24 Commw Mfg Company Arc welding unit
US3325760A (en) * 1965-10-01 1967-06-13 Gen Motors Corp Electromagnet with resinous ferromagnetic cladding

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4264683A (en) * 1978-07-26 1981-04-28 Permacoraltair, Inc. Metallic inductor cores
US4647890A (en) * 1986-05-15 1987-03-03 Battelle Development Corporation Molded ferromagnetic return circuit for a solenoid

Also Published As

Publication number Publication date
GB1322092A (en) 1973-07-04
NL7014813A (en) 1972-04-11
FR2110320B1 (en) 1976-06-04
US3829806A (en) 1974-08-13
FR2110320A1 (en) 1972-06-02
DE2146113A1 (en) 1972-04-13

Similar Documents

Publication Publication Date Title
US3775841A (en) Method of adjusting the dimensions of sintered ferromagnetic cores
US2269678A (en) Method of manufacturing coil structures
GB1421988A (en) Toroidal deflection yoke having conductors wound in flyback manner
US2567394A (en) Inductance coil
JPS60206122A (en) Choke coil
US3875543A (en) Toroidal core-coil combination with in situ molded end rings
JPS5916251A (en) Manufacturing method for deflection yoke core
JPH0140171Y2 (en)
JP2973440B2 (en) Manufacturing method of rotary transformer
US3859719A (en) Method of making a toroidal core-coil combination with in situ molded end rings
JPS5970154A (en) Small-sized motor
KR100228437B1 (en) Precision convergence system device
JPS59128736A (en) Manufacturing method of core for deflection yoke
JPH062252Y2 (en) Chip inductance element
JPS634326B2 (en)
JPH0473919A (en) Manufacture of coil assembly
JPH06260328A (en) Cylindrical anisotropic magnet and manufacture thereof
JPH09180650A (en) Deflection yoke
JPH01315118A (en) Manufacture of rotary transformer component
KR0144201B1 (en) CRT yoke deflection yoke core
JPS62128507A (en) Rotary transformer
JPS61126743A (en) Magnetic york for cathode-ray tube
JPH03225901A (en) Rotary transformer and manufacture thereof
JPH0449241B2 (en)
JPH05217517A (en) Deflection yoke